2010/11/3, Micha Silver <mi...@arava.co.il>: > On 11/03/2010 04:55 PM, Hanlie Pretorius wrote: >> Hi, >> >> I need to add some attributes from a soil polygon layer to a catchment >> polygon layer using area weighting. In other words, the contribution >> of the soil layer needs to be weighted by the amount with which its >> polygons overlap the catchment polygons. >> >> For example, suppose I want to weight soil infiltration rates. 30% of >> a catchment polygon overlaps with soil type 1 and 70% overlaps with >> soil type 2. Now I want a new attribute in the catchment polygon that >> takes 30% of the infiltration rate of soil type 1 and adds it to 70% >> of the infiltration rate of soil type 2. >> >> How can I do this in GRASS? >> > > The most straight forward way is using v.rast.stats. This module adds to > a vector attribute table the univariate statistics from a raster. So > you'll first convert the soil map to raster, then run v.rast.stats using > the catchment polygons as the vector and the soil infiltration as the > raster.
Thanks, this worked. Is there a reason (other than no one has had time to do it) that a similar function doesn't exist for two vector layers? _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user